Anomalies in quantitative measurement of 40K in natural samples

Journal of Radioanalytical and Nuclear Chemistry - Efficiency calibration by standard materials of known activity is usual protocol for γ-ray spectrometry. In general, 40K activity is measured...     

Selective N-monoalkylation of anilines catalyzed by a cationic ruthenium(II) compound

[(PPh₃)₂Ru(CH₃CN)₃Cl][BPh₄] has been found to catalyze the selective monoalkylation of anilines by alcohols.     

Concentration Dependent Transformation of Oligopeptide based Nanovesicles to Nanotubes and an Application of Nanovesicles

The concentration dependent transformation of an oligopeptide nanostructure from nanovesicles to nanotubes at neutral pH is presented. The oligopeptide Acp‐Tyr‐Glu (Acp: 6‐aminohexanoic acid) forms nanovesicles at a concentration of 6.9 mg mL^?1. At a concentration of 2.3 mg mL^?1 these vesicular structures completely disappear and nanotubular structures are observed. We have also successfully optimized an intermediate concentration (3.4 mg mL^?1) where an ordered array of fused vesicular structures are formed, which actually leads to the transition from nanovesicles to nanotubes. These vesicular structures are very much sensitive toward metal ions and pH. Biocompatible calcium ions and high pH (10.7) can trigger the rupturing of these nanovesicles. One important property of these nanovesicular structures is the encapsulation of a potent anticancer drug doxorubicin, which can also be released in the presence of calcium ions promising a future use of these nanovesicles as vehicles for carrying biologically important molecules.     

A quick accelerating microwave-assisted sustainable technique: permutated spiro-casing for imaging experiment

Molecular Diversity - A quick access tool for the one-pot, chromatography-free synthesis of the diversified dihydrospiro[indeno[1,2-b]pyridine-4,3′-indoline or...     

An investigation on the structure,spectroscopy, and thermodynamic aspects of clusters: A combined Parallel tempering and DFT based study

The problem of identifying low-energy structures of (n = 1-6) was investigated, and the evaluation of important properties like heat capacity, solvation energy, and vertical detachment energy for each of the clusters was carried out. The problem was handled at two different theoretical levels. First, an adequately chosen empirical potential energy surface was used to account for the major interactions between the constituents of the cluster studied. Once the surface was chosen, the Parallel tempering algorithm was employed to search out the low-energy critical points on this surface, which gave geometries at this level. To refine the structures further, these pre-optimized structures were used as inputs for quantum chemical evaluation to complete the final refinement. To check whether the structures found were reasonable, sensitive properties like heat capacity, solvation energy, and vertical detachment energy were calculated. Then, an effort was made to understand and explain the variations in these properties with change in the cluster size. To understand the process of cluster formation further, thermodynamic aspects like △H (298.15 K), △G (298.15 K), and heat capacity (C_v) changes were also evaluated. Infrared spectroscopic features were also studied to see whether the introduction of the ion caused reasonable shifts compared to a pure water cluster.     

The role of thiophosphoryl disulfide on the co‐cure of CR‐EPDM blends: effect of white fillers

Bis(diisopropyl) thiophosphoryl disulfide (DIPDIS) being a rubber accelerator has a definite role as a coupling agent in the silica filled polychloroprene rubber with ethylene propylene diene rubber (CR‐EPDM) blends. Diethylene glycol can further improve the beneficial effect of DIPDIS in silica filled CR‐EPDM blends. Two‐stage vulcanization technique further improves the physical properties of silica filled CR‐EPDM blends. The results have been compared with non‐reinforcing calcium carbonate filled systems. Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the silica filled CR‐EPDM blend vulcanizates obtained from this two‐stage process. Copyright © 2004 John Wiley & Sons, Ltd.     

Stokes phenomena and monodromy deformation problem for nonlinear Schrödinger equation

Following Flaschka and Newell, the inverse problem for Painleve IV is formulated with the help of similarity variables. The Painleve IV arises as the eliminant of the two second-order ordinary differential equations originating from the nonlinear Schrödinger equation. Asymptotic expansions are obtained near the singularities at zero and infinity of the complex eigenvalue plane. The corresponding analysis then displays the Stokes phenomena. The monodromy matrices connecting the solutionY _j , in the sectorS _j to that inS _j +1 are fixed in structure by the imposition of certain conditions. It is then shown that a deformation keeping the monodromy data fixed leads to the nonlinear Schrödinger equation. While Flaschka and Newell did not make any absolute determination of the Stokes parameters, the present approach yields the values of the Stokes parameters in an explicit way, which in turn can determine the matrix connecting the solutions near zero and infinity. Finally, it is shown that the integral equation originating from the analyticity and asymptotic nature of the problem leads to the similarity solution previously determined by Boiti and Pampinelli.     

高碘酸钾-二安替比林对碘苯基甲烷体系催化光度法测定痕量钌(Ⅲ)

合成了新试剂二安替比林对碘苯基甲烷（ＤＡｐＩＭ）,研究了在磷酸介质中钌（Ⅲ）催化高 碘酸钾氧化ＤＡｐＩＭ的显色反应,建立了一种测定痕量钉的催化光度分析法。方法的线性范 围为 ０～６ μｇ／Ｌ;检测限为１．６ × １０－７ｇ／Ｌ。该体系灵敏度高,稳定性好,用于矿样中痕量钉的 测定,其相对标准偏差为３．０％～４．１％,标准加入回收率为９７％１０５％。     

Green synthesis of water-dispersible silver nanoparticles at room temperature using green carambola (star fruit) extract

Journal of Sol-Gel Science and Technology - Silver nanoparticles (AgNPs) dispersible in water were synthesized at room temperature in the presence of carambola fruit extract at different pH. The...